Immune system-derived drug delivery system could help kill cancer cells with 50 times less chemo

While cancer remains one of the deadliest diseases, recent medical advances have made it much more manageable, and in some cases even curable. A new research, for instance, has found a way to enhance the cancer-fighting abilities of the drug paclitaxel, to a great extent. For the very first time, a team of scientists at the University of North Carolina at Chapel Hill has packed it in a non-toxic, dissolvable container made from the patient’s own immune system. Not only does it protect the drug from getting destroyed by the body’s defenses, the new approach actually increases its efficacy in killing stubborn cancer cells.

Led by Elena Batrakova, a professor at the UNC Eshelman School of Pharmacy’s Center for Nanotechnology in Drug Delivery, the team created the drug packaging using exosomes, which are basically microscopic spheres derived from white blood cells with the purpose of protecting the body from harmful infections. Composed of the same substance as cell membranes, exosomes are not treated by the individual’s body as foreign, and can safely be used in place of plastic-based drug delivery systems. Speaking about the project, recently published in Nanomedicine: Nanotechnology, Biology and Medicine journal, Batrakova said:

Exosomes are engineered by nature to be the perfect delivery vehicles. By using exosomes from white blood cells, we wrap the medicine in an invisibility cloak that hides it from the immune system. We don’t know exactly how they do it, but the exosomes swarm the cancer cells, completely bypassing any drug resistance they may have and delivering their payload.

Paclitaxel, which is commonly used to treat lung, breast and pancreatic cancers, usually causes some really serious and unpleasant side effects, including diarrhea, hair loss, joint and muscle pain and so on. It has also been found to greatly increase the risk of contracting serious infections, in patients with impaired immune system. As part of the current research, the team harvested exosomes from murine white blood cells, filling them up with specific quantities of paclitaxel.

To test the efficacy of the treatment, also known as exoPXT, the scientists added the drug to petri dishes containing different types of drug-resistant cancer cells. According to the researchers, the new approach required 50 times less drug to achieve the same cancer-annihilating effects as the plastic-based formulations currently used by doctors, like Taxol. Batrakova, the leader of the research team, explained:

That means we can use 50 times less of the drug and still get the same results. That matters because we may eventually be able to treat patients with smaller and more accurate doses of powerful chemotherapy drugs resulting in more effective treatment with fewer and milder side effects.

For further proof, the researchers applied the therapy to mouse models of drug-resistant lung cancers. To that end, they added a dye to the exosomes to be able to better track their movement through the lungs. As expected, the exosome-based drug was extremely effective in locating and destroying cancer cells, without affecting any of the healthy cells surrounding them. Batrakova added:

Accurately mapping the extent of tumors in the lungs is one of the biggest challenges in treating lung-cancer patients. Our results show how powerful exosomes can be as both a therapeutic and a diagnostic.

The research was conducted with funds from the National Institutes of Health, the Carolina Partnership and the Russian Federation Ministry of Education and Science.